Resources | Subject Notes | Physics
Know that the current estimate for H0 is $2.2 \times 10^{-18}$ per second.
The Hubble constant (H0) is a fundamental value in cosmology. It describes the rate at which the universe is expanding. It represents the velocity at which a galaxy is receding from us for every megaparsec (Mpc) of distance.
The value of H0 is not precisely known and is constantly being refined through ongoing astronomical observations. Current estimates place it around $2.2 \times 10^{-18}$ per second. This means that for every megaparsec further away a galaxy is, it is receding from us at a speed of $2.2 \times 10^{-18}$ meters per second.
The value of $2.2 \times 10^{-18}$ per second is incredibly small. This reflects the vast distances involved in the universe and the gradual nature of expansion over cosmic timescales.
| Parameter | Value | Units |
|---|---|---|
| Hubble Constant | $2.2 \times 10^{-18}$ | s-1 |
| Description | Rate of expansion of the universe | per second |
| Interpretation | For every 1 Mpc increase in distance, recession velocity increases by $2.2 \times 10^{-18}$ m/s |
The Hubble constant is crucial for understanding the age, size, and future evolution of the universe. It is a key parameter in cosmological models.